Connecting rod grinding jig



Nov. 4, 1947. E. LAPOINTE ET'AL 2,430,052

CONNECTING RODGRINDING-JIG Filed March 1o, 1945 2 srlfwts-sxwet 1 Patented Nov. 4, 1,947

FFICE CONNECTING ROD GRINDING JIG Louis E. Lapointe and Leandre J. Gaudet,

Worcester, Mass., assignors to Elmer H. Brunmark Application March 10, 1945, Serial No. V582,050

8 Claims.

rThis invention relates to apparatus and method for rebuilding and regrinding connecting rods to uniform and original size so that each connecting rod in the rebuilt motor will be exactly to size without tolerance and so that the connecting rods will have uniform centers for exact application to a crankshaft, it being understood however that both apparatus and method may be used to advantage in the manufacture of new motors as well as in rebuilding used motors.

Objects of the invention include the provision of apparatus and method for obtaining the results above described; and the apparatus comprises a jig effective to hold a plurality of connecting rods in temporary nearly aligned side by side condition, in combination with a centralizing bar of novel design which is used to flnally position the rods with their crankshaft bores in exact alignment, said jig having means to rigidly clamp the connecting rods in the nal position determined by the centralizing bar, so that when so clamped, the connecting rods may be bored in a single pass and ground simultaneously to Aexact and perfect likeness.

Further objects of the invention include the provision of a method of repairing worn connecting rods by removing the caps, milling or grinding olf a few thousandths at the ends of the caps and reapplying the latter to the rods to render the crankshaft bores smaller so that they may be bored and ground to exact original size in multiples by means of the jig above described.

Other objects and advantages of the invention will appear hereinafter.

Reference is to be had to the accompanying drawings, in which, v

Fig. 1 is a View in side elevation of a jig embodying the invention, parts being in section;

Fig. 2 is a section on line 2--2 of Fig. 1;

Fig, 3 is a View in end elevation of the rotary plates holding the connecting rods;

Fig. 4 is an elevational view of the centralizing bar, parts being in section;

Fig. 5 is an end elevational on a reduced scale of the jig;

Fig. 6 is a partial view of the centralizing bar looking in the direction of arrow 6 in Fig. 4; and

Fig. '7 is a section on line 'l-'l of Fig. 3.

As shown in Fig. 1, the present embodiment of the invention is disclosed as comprising a plate l0 adapted to be bolted or otherwise secured to the bed or platen of a grinding machine or the like, having an internal grinder l2 and desirably a boring head Nl mounted to feed in the direction of the arrows. Upstanding plates I6 and I8 are secured to plate l0 in spaced relation and carry a spindle 2i) rotatably mounting a sleeve 22, the sleeve being journaled in bearings 23, see Fig. '7. The upstanding plates i6 and I8 are provided with aligned apertures receiving bushings 24 slotted radially for the reception of four adjustable fingers 26 which are locked in position by adjusting screws 28. These ngers are provided with slots 30 for a purpose to be described.

Rotatably mounted with sleeve 22 there is a series of plates 32, these plates being 0f any desired number and having top and bottom arms 35i extending laterally therefrom, see Fig. 3. Plates 32 are spaced by hubs 3E and are secured together by bolts 38.

Each arm 34 is provided at each side thereof with a clamp member 40, Ll'l, and each arm and its clamps are adapted to be rigidly secured by bolts d2, the latter having stabilizing compression springs lla. Each pair of clamps has its own bolt 4:2 so that the pair of clamps at the right in Fig. 1 are secured by the upper bolt and the next inward pair of clamps are secured by the lower bo-lt, the latter having a passage 46 through the outer clamps for passage of a tool. Where there are four plates 32, the arrangement is such that the left hand clamps Il!) are secured from the left of the jig, i. e., oppositely from the bolts shown in Fig. 1. Clamps di] are each provided with a depending leg i8 having an adjustable pointed centering screw 50 therein, and. another leg 52 located by a dovetail 5d, legs 52 having adjustable centering screws 5S therein, the screws being disposed to point toward each other in spaced relation. All clamps @El and 4| are somewhat loose on arms 34 for adjustment of the clamps relative to the arms. The screws 56 are staggered, see Fig. 1, for a purpose to be described. I

Clamps 4l are provided with upstanding arms 58 having facing adjustable centering screws 60, which are also staggered.

Plate I8 is provided with a vertical arm B2 having a pin stop 64 thereon, and a pair of diametrically opposed adjustable stops 65 are provided on the right hand plates 32 to locate the rotatable plates correctly relative to the boring head and grinder.

The centralizing bar is shown in Figs. 4 and 6 and comprises a longitudinal spider 68 having end guides 10 for a pair of longitudinal fingers 'i2 provided with cams 'M at their free ends coacting with stop blocks 'I6 to radially extend the latter as the fingers 12 move inwardly. Blocks 76 are held to the bar by an annular spring 18,

and are located in rings 80 by flat springs 82. Fingers l2 are moved inwardly by a spring 84 which bears on a block 86 mounted on a spindle 88 threaded into spider 68 at 90. Spindle 88 has a handle 92 for turning the same and as the spindle is rotated to take into the spider, the spring 84 is compressed and resiliently moves the nngers l2 to resiliently expand blocks 'i6 radially outwardly. Spindle 88 is provided with a collar 94 to which is connected other fingers 96, the. latter being positively slid inwardly simultaneously to radially expand blocks 98 similar to blocks 16. It will be seen that the centralizing bar is symmetrical and by turning the handles 92 simultaneously, the blocks will be uniformly moved radially outwardly.

In the operation of the device, the connecting rod caps lill) are removed from the connecting rods and milled or ground oif at their ends Vand replaced, thus making the crankshaft bores smaller and elliptical. The connecting rods are then placed in the jig with clamps 4b and 4i loose, the centering screws being used to hold the -rods in place. As indicated in Figs. l and 3, the rods are alternately oiset so that the connecting rod pin bores are alternately aligned to allow the rods to be mounted in close relation, see Fig. l. The centralizing rod is inserted in the bushings .24 with the stop blocks entering the slots .3D 1in fingers 25, the bushings or ngers holding the centralizing bar in correct position. The stop blocks being 'located adjacent the iirst -two connecting rods, handles 92 are simultaneously turned to move the stop blocks radially. The blocks impinge on the .interior periphery of the connecting rods and adjust the vsame to a common center in alignment with the boring and grinding tools, whereupon bolts 42 are tightened up, thus securing the clamps @il and 4I in tight clamped relation. The centralizing bar is then -moved to do the same for the next two connecting rods, etc. The resiliently moved blocks 'I6 are always located on the minor axis of the elliptical lcrankshaft bores and the mechanical blocks 98 are located on the major axis, because the shorter axis .of the bores will be contacted by the blocks .before the 'longer axis. When the connecting rods fhave all been correctly located, the boring tool istfbrought in and a small cut'will achieve a uniform circular bore in all rods, whereupon the :grinder is used to polish the bore surfaces exactly to new specification.

I'By the use of the method and apparatus above described, connecting rods may be given exactly uniform crankshaft bores exactly in line on a common axis, and the pin bores may then be exactly vreinished using the crankshaft bores as a base point. In addition, the crankshaft bores are all exactly to new car specification and new full :floating bearings can be used without change.

YWe claim:

1, Apparatus of the class described comprising -a series of plates arranged in spaced relation, -means spacing and securing the plates, movable :clamps on each plate, said clamps being arranged in `opposed pairs, centering pins in each clamp to position pieces at each end thereof, means to move the clamps and positioned pieces to aline the same, and means to rigidly secure the clamps to the plates.

2. Apparatus of the class described comprising a series of generally parallel plates, means spacing and securing the plates, a pair of clamps on each plate, said clamps facing each other and being effective to receive a connecting rod, centering means in each clamp to position both ends of the rod relative to the clamps, said clamps being movable in unison with the rod, and means to rigidly secure the clamps to the plates.

V3. Apparatus of the class described comprising a series of spaced parallel plates, means spacing and securing the plates together, a pair of clamps movably positionedat each end of each plate, means on the clamps to secure connecting rods therein at each end of the rods, means to individually move the rods and their attached clamps to centralize the crankshaft bores of the rods, means to rigidly secure the clamps to the plates and thereby the rods in adjusted relation to each other, and means to work on the crankshaft bores.

4. Apparatus of the class described comprising a series of holders, each holder having a pair of movable clamps secured thereto in spaced relation, one clamp being adapted to hold the crankshaft bore-end of Va connecting rod and the other clamp on each holder being adapted to hold the pin end of the rod, so that the rods and clamps are rindividually movable relative to the holders, means to internally centralize the rods at the crankshaft bores on a common axis in a series, means to rigidly secure the clamps and thereby the rods to the holders, and a tool to work the crankshaft bores.

5. The apparatus of claim 4 including a shaft rotatably mounting the holders, and additional lclamps on the holders for securing a second series of connecting rods, and stops for selectively locating the holders with the crankshaft bores of either series in operative relation to the tool.

6. A centralizing bar comprising a central support, a series of longitudinal sliding fingers on `the support, blocks having cam engagement with -the fingers for outward movement under influence of the fingers, and means to slide the iingers, said nngers being angularly spaced about the axis of the bar.

'7. The bar of claim 6 wherein said means includes a resilient element to yieldingly slide the ingers.

8. The bar of claim 6 wherein said means includes a resilient element to yieldingly slide certain of the ngers and a mechanical element to .positively slide the remaining ngers.

LOUIS E. LAPOINTE. LEANDRE J. GAUDET.

REFERENCES CITED The following references are of record in the file of this patent:

UMTED STATES PA'I'ENTS Number Name Date 1,939,205 Connor s Dec. l2, 1933 2,053,584 Sunnen Sept. 8, 1935 

